Foreign backed militants were putting up a fierce fight around the villages of Debaa and Buwayda as Syrian security forces attacked the territory, activists and local media in the area said.
The villages were enduring heavy clashes organized by army troops after the total seizure of nearby districts.
Victory of Qusayr after a two-week operation by Syrian army soldiers was a significant gain for Syrian people.
Qusayr is in central Homs province, which borders Lebanon in the west and Iraq in the east.
Debaa is 5 km (3 miles) northeast of Qusayr and Buwayda another 7 km in the same direction.
Freeing Qusayr from terrorists not only cuts foreign backed militants' supply lines, but will also help troops regain control of central Syria and isolate terrorists bastions in the north and south.
It also strengthens the Syrian government's hand before a peace conference which Russia and the United States are trying to organize under UN auspices in Geneva, possibly in July.